Combination of A-Naphthol with Paratoluidine. " " Metanitroaniline. " " Nitroparatoluidine. " B-Naphthol with Aniline. " " Paratoluidine. " " Orthoamidoazotoluene. The samples were tested for fastness to light by exposing them for nine days with the following results:-- _Fast._ Combination of A-Naphthol with Aniline. " " Toluidine. " " Metanitroaniline. " " Paranitroaniline. " " Nitroparatoluidine. " " B-Naphthylamine. " " Amidoazobenzol. " " Orthoamidoazotoluol. " B-Naphthol with Aniline. " " Paratoluidine. " " Metanitroaniline. " " Paranitroaniline. " " B-Naphthylamine. " " A-Naphthylamine. _Moderately Fast._ Combination of B- Naphthol with Nitroparatoluidine. _Very Loose._ Combination of A-Naphthol with Toluidine. " " A-Naphthylamine " B-Naphthol with Toluidine. " " Amidoazobenzene. " " Orthoamidoazotoluene. The most important of the naphthol colours is undoubtedly paranitroaniline red, produced by the combination of paranitroaniline and beta-naphthol. In order to produce the best and brightest shades these two bodies must be quite pure. The following directions may be followed:-- =Dyeing Paranitroaniline Red on Yarn.= It unfortunately happens that this red does not admit of being worked in large quantities at a time, particularly in the diazo bath where the colour is developed, as the previous operations seem to render the yarn slightly waterproof, and hence if large quantities of yarn were dealt with at one time some would be found to be dyed all right, others would be defective. It has, therefore, been found best to work only about 2 lb. of yarn at a time, carefully carrying out each operation with this quantity. As, however, the process can be quickly worked it follows that in the course of a day a fairly large quantity of yarn can be treated. 1. _Grounding._ The grounding or preparing bath for 100 lb. of yarn is best made in the following manner: 4 lb. of beta-naphthol are stirred in 2-1/2 lb. of caustic soda liquor 70 deg. Tw., then 1-1/2 quarts of boiling water is added, when dissolved 1-1/2 quarts of cold water. In a separate vessel dissolve 5 lb. Turkey-red oil in 11 quarts of water, then mix the two liquors together and add sufficient water to make up the whole to 12 gallons.